What antibiotics are used to treat impetigo?

Antibiotic Treatment for Impetigo

For impetigo treatment, topical mupirocin 2% ointment is the first-line therapy for limited disease, while oral antibiotics such as dicloxacillin, cephalexin, or clindamycin are recommended for extensive disease, with clindamycin being preferred when MRSA is suspected. 1, 2

Types of Impetigo and Causative Organisms

Impetigo presents in two main forms:

• Nonbullous impetigo (70% of cases): Caused by Staphylococcus aureus or Streptococcus pyogenes
• Bullous impetigo (30% of cases): Caused exclusively by S. aureus 1, 3

Treatment Algorithm

1. Limited Disease (Few Lesions)

• First-line: Topical mupirocin 2% ointment applied three times daily for 7 days 1, 2
  • Highly effective against both S. aureus and S. pyogenes
  • FDA-approved specifically for impetigo treatment 2
• Alternatives:
  • Retapamulin
  • Fusidic acid (not available in all countries) 1

2. Extensive Disease (Multiple Lesions or Widespread)

• For MSSA infections:
  • Dicloxacillin or cephalexin for 7 days 1
• For confirmed streptococcal infections:
  • Oral penicillin for 7 days 1
• For suspected or confirmed MRSA:
  • Clindamycin 300mg three times daily for 7-10 days 1
  • Provides excellent coverage against both MRSA and streptococci

3. Treatment Duration

• Standard duration: 7 days for oral antibiotics
• Evaluate clinical response within 48-72 hours 1
• Expected resolution within 7-10 days of starting appropriate treatment 1

Evidence-Based Comparisons

• Topical vs. Oral: Topical mupirocin has shown similar or superior efficacy to oral erythromycin in clinical trials 4, 5
• Side Effects: Oral antibiotics cause more side effects, particularly gastrointestinal issues, compared to topical treatments 5
• Resistance Concerns:
  • Trimethoprim-sulfamethoxazole (TMP-SMX) has inadequate streptococcal coverage 1, 3
  • Penicillin is inferior to other antibiotics for impetigo treatment 3, 5

Important Clinical Considerations

• MRSA Awareness: Community-acquired MRSA (CA-MRSA) is an increasing concern as an etiological agent 1
• Culture Indications: Consider bacterial culture and sensitivity testing if no improvement after 3-5 days 1
• Pediatric Considerations: Avoid tetracyclines (doxycycline, minocycline) in children under 8 years due to risk of inhibiting bone growth 1

Common Pitfalls to Avoid

• Failing to consider MRSA in recalcitrant cases
• Using penicillin as first-line therapy (inferior efficacy)
• Inadequate duration of therapy
• Relying solely on topical therapy for extensive disease
• Using topical disinfectants (inferior to antibiotics) 1, 6
• Using TMP-SMX for streptococcal impetigo (inadequate coverage) 1, 3

Prevention Measures

• Keep lesions covered when possible
• Use separate towels and linens
• Practice good hand hygiene
• Prompt identification and treatment of cases 1